Innovative Development and Functional Capabilities of Ethylcellulose-ZnO Transparent Films as the Next Generation of Active Packaging Materials

In the packaging sector, biobased and biodegradable materials have garnered increasing interest due to their potential to mitigate the environmental impact of fossil-based plastics. In pursuit of sustainable alternatives to plastic packaging, we present a novel approach utilizing ethyl cellulose (EC) and zinc oxide nanoparticles (ZnO NPs) to develop sustainable polymer nanocomposite films. These films, with uniform thickness (~65 µm) and varying ZnO NP weight percentages were synthesized via in situ synthesis and ultrasonication for uniform dispersion. Comprehensive assessments of surface structures, optical properties, mechanical strengths, and antimicrobial efficacies were conducted, revealing promising enhancements compared to EC films. FTIR revealed interactions between carboxyl groups of EC and ZnO NPs. XRD and HRTEM confirmed ZnO's hexagonal wurtzite structure with a particle size of 30–35 nm. FESEM images showed uniformly dispersed ZnONPs in the films. Energy dispersive X-ray (EDX) spectroscopy analysis validated the purity of ZnO nanoparticles and the homogeneity of the nanocomposite film. UV-visible spectroscopy indicated increased optical band gaps (up to 3.26 eV), augmenting their potential applications in energy sectors. Mechanical analysis showcased enhanced tensile strength (43.98 MPa). Moreover, a higher thermal stability (maximum degradation temperature of 335°C) was achieved. AFM illustrated improved hydrophobicity. Crucially, all composite films exhibited superior antibacterial properties against S. aureus and E. coli, as confirmed by FESEM analysis, underscoring their efficacy as antimicrobial packaging materials.